EP3377140B1 - Dialysis device comprising heating and cooling mechanism - Google Patents

Description

The invention relates to a dialysis machine with an extracorporeal blood system, a dialysis fluid system, a dialyzer and a control unit.

Dialysis machines according to the preamble of claim 1 are known from the prior art. Such devices are used in the context of dialysis treatment to remove urea and other substances from the blood of a patient with no or reduced kidney activity. The central element of a dialysis machine is the dialyzer, which is a filter unit with a blood chamber and a dialysis fluid chamber, which are separated by a semipermeable membrane. The substances to be removed from the blood pass through the semipermeable membrane in the dialyzer from the blood chamber into the dialysis fluid chamber.

For example, from the publication DE102008062424A1 a method for reducing blood clotting in the circuit of a device for replacing the kidney function is known. The reduction of blood coagulation in the circuit of the device for replacing the kidney function is achieved by the fact that before entering the device for replacing the kidney function, the blood after leaving the body of the The patient is cooled to a temperature in the range of 10 ° to 30 ° C, that after the blood has passed through the device for replacing the kidney function, the blood is warmed to a temperature at least close to body temperature and that the blood then enters the patient's body is returned.

In addition, from the patent specification US6156007A a method for treating a patient by means of hyperthermia is known in which blood taken from a patient is first heated to a temperature above body temperature by means of a dialysis machine, and is then heated again after exiting the dialyzer of the dialysis machine, causing hyperthermia of the patient is achieved. From the EP2995329 A1 , which belongs to the prior art according to Article 54 (3) EPC, a device for extracorporeal blood treatment with a heating device is known.

In order to increase the efficiency of the treatment, it is desirable to achieve the highest possible throughput of the undesired substances from the blood chamber into the dialysis fluid chamber.

Against this background, the invention relates to a dialysis machine with an extracorporeal blood system, a dialysis fluid system, a dialyzer and a control unit. According to the invention, the dialysis machine has a heating mechanism for heating the blood in the extracorporeal blood system before entering the dialyzer or in the dialyzer and a cooling mechanism for cooling the blood in the extracorporeal blood system after it leaves the dialyzer. The control unit is designed in such a way that the blood is heated to a dialysis temperature above the patient's body temperature before entering the dialyzer or in the dialyzer, and is cooled again to the patient's body temperature after exiting the dialyzer.

The invention makes use of the knowledge that an increase in the blood temperature in the dialyzer has a positive effect on the cleaning performance in the Dialyzer has. The increase in blood temperature can take place outside of the body using different devices. It is essential for the safety of the patient that the blood flowing back has body temperature again (with a certain tolerance range).

The increase in temperature influences the cleaning performance in the dialyzer due to several effects. For example, the diffusion increases with increasing temperature, while the viscosity of the blood decreases. Furthermore, at elevated temperature the balance between bound toxins, e.g. Albumin-bound toxins, which are not membrane-permeable, and free toxins, which are membrane-permeable, shifted in the direction of the free toxins. These effects add up and overall lead to a significantly higher cleaning performance.

In one embodiment, the dialysis temperature is between 37 ° C and 46 ° C, preferably between 40 ° C and 46 ° C and more preferably between 42 ° C and 45 ° C. At temperatures beyond the limit of around 46 ° C, denaturation and other undesirable effects can set in in the blood.

In one embodiment, the heating mechanism comprises a heating device arranged upstream of the dialyzer in the dialysis fluid system. In this embodiment, the control unit is designed in such a way that the dialysis fluid is heated to a temperature that is greater than or at least equal to the dialysis temperature before it enters the dialyzer. The blood can be heated to the dialysis temperature by heat exchange in the dialyzer. With a given type of dialyzer, the degree of warming caused by the heat exchange can be achieved by regulating the flow of the dialysis fluid and the blood in the dialyzer and by setting the temperature of the dialysis fluid.

In one embodiment, the dialysis machine comprises a substitution fluid system which comprises a predilution line opening into the extracorporeal blood system upstream of the dialyzer and / or a postdilution line opening into the extracorporeal blood system on the return side of the dialyzer.

In one embodiment, the heating mechanism comprises a heating device arranged upstream of the mouth of the predilution line in the substitution fluid system. In this embodiment, the control unit is designed in such a way that the substitution fluid is heated through the predilution line to a temperature that is greater than or at least equal to the dialysis temperature before it enters the extracorporeal blood system. The blood can be heated to the dialysis temperature by adding a warm substitution fluid before entering the dialyzer. The degree of warming can be determined by your regulation of the rivers the substitution fluid and the blood as well as by adjusting the temperature of the substitution fluid.

In one embodiment, the substitution fluid system is integrated into the dialysis fluid system and the heating devices for the dialysis fluid and the substitution fluid can correspond to one another.

In one embodiment, the cooling mechanism comprises a cooling device arranged upstream of the mouth of the post-dilution line in the substitution fluid system. In this embodiment, the control unit is designed in such a way that the substitution fluid is cooled down through the post-dilution line before it enters the extracorporeal blood system to a temperature that is less than or at most equal to body temperature.

In one embodiment, the cooling mechanism comprises a branch for substitution fluid which is arranged upstream of the heating device in the substitution fluid system and whose temperature is less than or at most equal to body temperature. In this embodiment, the control unit is designed in such a way that the substitution fluid is branched off before entering the heating device and is not heated to body temperature through the post-dilution line before it enters the extracorporeal blood system.

Instead of the branch, there can also be separate substitution fluid systems for predilution and post-dilution.

For example, the blood can be cooled down from the dialysis temperature to body temperature by adding a cool substitution fluid after it has left the dialyzer. The degree of cooling can be determined by your regulation of the rivers the substitution fluid and the blood as well as by adjusting the temperature of the substitution fluid.

In one embodiment, the heating mechanism comprises a heating device arranged upstream of the dialyzer in the blood system. In one embodiment, the cooling mechanism comprises a cooling device arranged in the blood system on the return side of the dialyzer. In this way, the blood can be heated or cooled directly.

Essentially, it is possible to increase the blood temperature through indirect heating (e.g. water heater), introduction of heated liquid (warm predilution, heated citrate is also conceivable with CiCa anticoagulation) or through heat exchange in the dialyzer itself (warm dialysate). Indirect cooling of the blood (Peltier element, cooling element, etc.) is also conceivable.

In one embodiment, the heating device is a flow heater arranged on a line of the respective fluid system. The cooling device can be a through-flow cooler arranged on a line of the respective liquid system.

In one embodiment, the heating device comprises a heat exchanger, for example a spiral heat exchanger, a Peltier element and / or a heating bag, as the heating element. The cooling device can comprise a heat exchanger, for example a spiral heat exchanger, a Peltier element and / or a cooling bag as the cooling element.

In one embodiment, the dialysis machine has an addition system for an anticoagulant liquid such as, for example, a citrate solution or a heparin solution, which is fed into a supply side and / or return side of the dialyzer the extracorporeal blood system comprises access line opening. On the basis of this addition system and the temperature control of the anticoagulant liquid, a temperature control or a contribution to temperature control can also be achieved, as was explained in connection with the substitution agent liquid system.

To control the temperature of all liquids, temperature sensors can be arranged at suitable points in the dialysis machine, which sensors are connected to the control unit. For example, a temperature sensor can be arranged in front of or on the dialyzer in the extracorporeal blood system in order to monitor the temperature of the blood in front of or in the dialyzer. Furthermore, a temperature sensor can be arranged in the blood system on the return side of the cooling device or mouth in order to monitor the temperature of the blood before reinfusion to the patient. Furthermore, a temperature sensor can be arranged upstream of the dialyzer in the dialysis fluid system in order to monitor the temperature of the dialysis fluid upstream of the dialyzer. A temperature sensor can also be arranged in front of the mouth in the pre- and / or post-dilution line of the substitution fluid system in order to monitor the temperature of the substitution fluid before it enters the extracorporeal blood system.

Both the heating mechanism and the cooling mechanism can combine several different of the mentioned corresponding mechanisms.

Preferably, the temperature of the heated dialysis fluid solution, substitution solution or anticoagulant solution or the temperature of the heating elements arranged on the blood system does not exceed a temperature of 46 ° C in order not to cause local denaturation of blood components during the addition or at the contact point.

A dialysis process can be carried out using the dialysis machine according to the invention, the blood being heated to the dialysis temperature before entering the dialyzer or in the dialyzer and being cooled down again to the patient's body temperature after leaving the dialyzer.

Figur 1:

eine modellierte Darstellung der Änderung des Diffusionskoeffizienten D in wässriger Lösung nach Stokes-Einstein-Gleichung;

Figur 2:

eine schematische Darstellung einer Ausführungsform eines erfindungsgemäßen Dialysegeräts;

Figur 3:

eine schematische Darstellung einer weiteren Ausführungsform eines erfindungsgemäßen Dialysegeräts;

Figur 4:

eine schematische Darstellung einer weiteren Ausführungsform eines erfindungsgemäßen Dialysegeräts; und

Figur 5:

eine schematische Darstellung einer weiteren Ausführungsform eines erfindungsgemäßen Dialysegeräts.

Further details and advantages of the invention emerge from the exemplary embodiments illustrated below with reference to the figures. In the figures show:

Figure 1:

a modeled representation of the change in the diffusion coefficient D in aqueous solution according to the Stokes-Einstein equation;

Figure 2:

a schematic representation of an embodiment of a dialysis machine according to the invention;

Figure 3:

a schematic representation of a further embodiment of a dialysis machine according to the invention;

Figure 4:

a schematic representation of a further embodiment of a dialysis machine according to the invention; and

Figure 5:

a schematic representation of a further embodiment of a dialysis machine according to the invention.

A modeled representation of the change in the diffusion coefficient D in aqueous solution according to the Stokes-Einstein equation is shown in Figure 1 shown. The Stokes-Einstein equation describes the diffusion coefficient as a function of the temperature T, the viscosity η of the solvent and the radius r of the diffusing molecule. $$\mathrm{D.}={\mathrm{k}}_{\mathrm{B.}}\cdot \mathrm{T}/\mathrm{6th}\cdot \mathrm{\pi }\cdot \mathrm{\eta }\cdot \mathrm{r}=\mathrm{const}\cdot \mathrm{T}/\mathrm{\eta }\left(\mathrm{T}\right)$$

The viscosity of the water (plasma) is also temperature-dependent. In the representation according to Figure 1 therefore the ratio T / η and its relative change in relation to 37 ° C is shown as a function of temperature. With a temperature increase from 37 ° C to 46 ° C (ΔT = + 9K), the diffusion coefficient D increases by 20% for all molecules.

In Figure 2 a first embodiment of a dialysis machine according to the invention is shown schematically.

The dialysis machine comprises an extracorporeal blood circuit 1 and a dialysis fluid circuit 2, which come into contact with one another on a dialyzer 3. The dialyzer 3 comprises a semipermeable membrane 4 which separates a blood chamber 5, which forms part of the extracorporeal blood circuit 1, and a dialysis fluid chamber 6, which forms part of the dialysis fluid circuit 2. The directions of flow of the blood and the dialysis fluid in the different chambers 5 and 6 of the dialyzer 3 are opposite. The directions of flow in the circuits are indicated in the figure with arrows.

A blood pump 8 is located in the arterial blood line 7 and a drip chamber 10 is located in the venous blood line 9. The arterial port and the venous port 12 for connecting the patient are identified by the reference numerals 11 and 12.

The feed line 13 of the dialysis fluid circuit 2 is connected to a dialysis fluid source 14. The source can be, for example, a machine-specific reservoir or a act machine-specific continuous mixing unit: It is also conceivable that the source 14 represents a central supply unit of a dialysis center. The return line 15 of the dialysis fluid circuit 2 is connected to an outlet 16.

The dialysis machine also has a control unit 17 which, among other things, determines the flow rates in the extracorporeal blood circuit 1 and in the dialysis fluid circuit 2 using the pump 8 and others in Figure 2 regulates actuators not shown but known to those skilled in the art.

According to the invention, the dialysis machine has a heating mechanism for heating the blood as it passes through the dialyzer 3. In the embodiment shown, the heating mechanism comprises a heating device 18 which is arranged in the source 14 or in the feed line 13 and which is connected to the control unit 17 (not shown in the figure). This heating device 18 is controlled by the control unit 17 in such a way that dialysis fluid, before it enters the dialysis fluid chamber 6 of the dialyzer 3, is increased to a temperature which is above the body temperature of the patient. As a result of heat exchange at the semipermeable membrane 4, the blood is continuously heated as it passes through the blood chamber 5 of the dialyzer 3 until it reaches a dialysis temperature near the venous outlet of the dialyzer 3, which is preferably above 40 ° C. As a result, an increased cleaning performance is achieved at least in the venous half of the dialyzer 3 due to the effects described above. The temperature of the dialysis fluid entering the dialyzer 3 can be monitored, for example, using a temperature sensor (not shown in the figure), which is located in the flow line 13 of the dialysis fluid circuit 2, preferably near the dialyzer 3, and is also connected to the control unit 17.

In order to cool the blood, which was heated in the dialyzer 3 to a dialysis temperature above the patient's body temperature, to body temperature again before reinfusion into the patient at the venous port 12, the dialysis machine also has a cooling mechanism that includes a heat exchanger 19 includes in the venous line 9. The heat exchanger 19 can be designed, for example, as a spiral heat exchanger, the blood being brought into thermally conductive contact with a cooling liquid which has a temperature below body temperature. The heat exchanger or the fluid pump for the cooling liquid is also connected to the control unit 17. To monitor the blood temperature before reinfusion at the venous port 12, a temperature sensor, not shown in the figure, which is also connected to the control unit, can be present in the venous line 9, preferably near the venous port 12 and in any case between the heat exchanger 19 and the venous port 12 17 is connected.

In Figure 3 Another embodiment of a dialysis machine according to the invention is shown, the same parts being provided with the same reference numerals.

The cooling mechanism comprises a post-dilution line 20, which branches off from the feed line 13 at a point 21. A liquid pump 22 is arranged within the post-dilution line. The post-dilution line 20 opens into the venous line 9 at the drip chamber 10.

In this embodiment, a heating device 23 is provided between the branch point 21 and the dialyzer 3 in the feed line 13. It is thus possible to further increase the temperature of the dialysis fluid which is supplied to the dialyzer 3 after the substitution solution has been branched off for the post-dilution. In this respect it can be provided that the dialysis fluid during the Provision in the source 14 is not heated or at least not heated to body temperature and is branched off into the post-dilution line 20 at the branch point 21 in this still cool state. Only between the branching point 21 and the dialyzer 3 does the heating device 23 increase the temperature to above body temperature, so that the already in connection with the embodiment according to FIG Figure 1 Set the heating effects of the blood shown in the dialyzer 3.

The heating device 23 and the pump 22 are connected to the control unit 17.

Compared to the device according to Figure 1 however, after leaving the dialyzer 3, the blood is not cooled by an additional cooling unit 19 but by the addition of substitution solution which is at a temperature below body temperature. The advantage of this solution is that no heating and / or cooling element is necessary on the extracorporeal blood circuit 1.

In Figure 4 shows a further embodiment of the invention, wherein like parts are again marked with identical reference numerals. This embodiment is according to the embodiment Figure 3 similar, with the only difference that instead of the heating device 23 in the flow line 13, a cooling device 24 is arranged in the post-dilution line 20. The dialysis fluid is thus, as is also the case in the embodiment according to FIG Figure 2 was the case, already increased to a temperature above body temperature during the provision and branched off into the post-dilution line 20 at branch point 21 also at an increased temperature. The dialysis or substitution fluid is then cooled in the post-dilution line 20 by the cooling device 24 before it is introduced into the venous line 9 of the extracorporeal blood circuit 1. This embodiment has compared to the embodiment according to Figure 3 the advantage of using selective cooling the substitution fluid in the post-dilution line 20 has an improved controllability of the cooling power.

The cooling device 24, the heating device 18 and the pump 22 are connected to the control unit 17.

In the embodiments according to Figures 3 and 4th For example, a temperature sensor can be present in the post-dilution line 20, preferably near the drip chamber 10, in order to be able to determine the temperature of the substitution solution added into the venous line 9. This temperature sensor is in turn connected to the control unit 17.

Figure 5 shows a further embodiment of a dialysis machine according to the invention, the difference compared to the embodiment according to FIG Figure 2 consists in that a predilution line 25 is provided, with the aid of which substitution solution is branched off from the source 14 and mixed into the arterial line 7 at a mixing point 26 between the pump 8 and the dialyzer 3.

In the predilution line 25 there is a pump 27. In this embodiment, there is the possibility of introducing substitution solution heated to a temperature above the body temperature of the patient into the arterial line 7 in the source 14 and thus the blood already before entering the dialyzer 3 To heat dialysis temperature of, for example, greater than 40 ° C. In this way, the treatment efficiency can be increased over the entire dialyzer. Further heating by using a dialysis fluid heated above body temperature on the dialysis fluid side 6 of the dialyzer 3 is also possible.

In this embodiment it is preferably provided to provide a temperature sensor in the predilution line 25 near the injection point 26 and to connect this to the control unit 17 in order to be able to monitor the temperature of the injected substitution solution. The pump 27 is also connected to the control unit 17.

Claims (10)

1. A dialysis device comprising an extracorporeal blood system, a dialyzing fluid system, a dialyzer (3) and a control unit (17),
   characterized in that
   the dialysis device has a heating mechanism for heating the blood in the extracorporeal blood system before entry into the dialyzer or in the dialyzer as well as a cooling mechanism for cooling the blood in the extracorporeal blood system after exiting the dialyzer (3); and in that the control unit (17) is configured such that the blood is heated before entry into the dialyzer (3) or in the dialyzer (3) to a dialysis temperature which is above the body temperature of the patient and is cooled back to the body temperature of the patient after exiting the dialyzer(3).
2. A dialysis device in accordance with claim 1, characterized in that the dialysis temperature is between 37°C and 46°C, preferably between 40°C and 46°C, and further preferably between 42°C and 45°C.
3. A dialysis device in accordance with one of the preceding claims, characterized in that the heating mechanism comprises a heating apparatus (18) arranged at the feed side of the dialyzer (3) in the dialyzing fluid system; and in that the control unit (17) is configured such that the dialyzing fluid is heated before entry into the dialyzer (3) to a temperature which is larger than or at least equal to the dialysis temperature.
4. A dialysis device in accordance with one of the preceding claims, characterized in that the dialysis device furthermore has a substitution fluid system which comprises a pre-dilution line (25) opening at the feed side of the dialyzer (3) into the extracorporeal blood system and/or a post-dilution line (20) opening at the return side of the dialyzer (3) into the extracorporeal blood system.
5. A dialysis device in accordance with claim 4, characterized in that the heating mechanism comprises a heating apparatus (18) arranged at the feed side of the opening of the pre-dilution line (25) in the substitution fluid system; and in that the control unit (17) is configured such that the substitution fluid is heated before entry into the extracorporeal blood system through the pre-dilution line (25) to a temperature which is larger than or at least equal to the dialysis temperature.
6. A dialysis device in accordance with claim 5, characterized in that the cooling mechanism comprises a cooling apparatus (24) arranged at the feed side of the opening of the post-dilution line (20) in the substitution fluid system; and in that the control unit (17) is configured such that the substitution fluid is cooled before entry into the extracorporeal blood system through the post-dilution line (20) to a temperature which is less than or at a maximum equal to body temperature.
7. A dialysis device in accordance with claim 5, characterized in that the cooling mechanism has a branch for substitution fluid arranged at the feed side of the heating apparatus (18) in the substitution fluid system, the temperature of the substitution fluid being less than or at a maximum equal to body temperature; and in that the control unit (17) is configured such that the substitution fluid is branched off before entry into the heating apparatus (18) and is not heated up to body temperature through the post-dilution line (20) before entry into the extracorporeal blood system.
8. A dialysis device in accordance with one of the preceding claims, characterized in that the heating mechanism comprises a heating apparatus (23) arranged at the feed side of the dialyzer (3) in the blood system; and/or in that the cooling mechanism comprises a cooling apparatus (24) arranged at the return side of the dialyzer (3) in the blood system.
9. A dialysis device in accordance with one of the claims 3 to 8, characterized in that the heating apparatus (18, 23) is a flow heater arranged at a line of the respective fluid system; and/or in that the heating apparatus (18, 23) comprises a heat exchanger (19), for example a spiral heat exchanger, a Peltier element and/or a heating pack, as a heating element.
10. A dialysis device in accordance with one of the claims 3 to 9, characterized in that the cooling apparatus (24) is a flow cooler arranged at a line of the respective fluid system; and/or in that the cooling apparatus (24) comprises a heat exchanger (19), for example a spiral heat exchanger, a Peltier element and/or a cooling pack, as a cooling element.

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